The FeministWiki infrastructure consists of many services, which all members can use. Whenever a service requires a username and password to use, you can use your global FeministWiki username and password for it.
The primary service is of course the wiki, which you are currently reading a page of. The wiki contains information about Feminism, and about the FeministWiki project itself. All members can edit the wiki. Non-members can only read it.
FeministWiki hosts a chat server, to which you can connect through the page above. You can see who's online via the small "speech bubble" (crossed with an "x" for those who are offline), and start chatting with them immediately. You can also join a group chat, for example "feminism".
The chat server is in fact an XMPP (aka Jabber) server, meaning you can also connect to it with any XMPP client such as Gajim, Pidgin, Xabber (Android), or ChatSecure (iOS). Your JID for the connection is email@example.com and your password the usual.
The FeministForum is the "bulletin board" style forum of the FeministWiki community. (If you don't know what a "bulletin board" style forum is: another popular example is Mumsnet.) It can be used for all kinds of discussion between members, not just feminism.
The forum is divided into sections and subsections. Feel free to ask the technician to add more sections to the forum. By default, all sections are set up such that only members can write, but everyone can read what's written in the forum. However, sections of the forum can also be set up so that only FeministWiki members can see what's written.
The forum is open to languages other than English; just ask the technician to add a section and subsections for your language, and they will be added if there's enough demand.
Every FeministWiki member automatically has an email account like "firstname.lastname@example.org" and can send and receive emails with it.
The easiest way to use your email account is to simply visit the link above and log in with your FeministWiki username and password.
Here are the connection parameters if you want to configure your own email client for your FeministWiki email account:
Just like DropBox, you can use the page above to upload arbitrary files so you have them stored on the FeministWiki platform. As usual, log in with your FeministWiki username and password.
For old-school people, the FeministWiki offers its own IRC server, which only members can use.
You can connect to the IRC server at irc.feministwiki.org with TLS on port 6697, but you need to correctly configure your client for the server to accept the connection. The server uses the plain old "PASS" authentication method, where your client provides a password as part of the initial connection parameters. For the server to accept your connection, your nick must correspond to your FeministWiki username and the password provided via the "PASS" command must be your FeministWiki password.
Adding new members
Finally, there's a small service that allows any member to add new members. Enter your username and password, and then the username for the new member to add, and click "Add member". If everything goes right, a simple text page will tell you the password for the new user. Contact the new member and notify them of their username and password, informing them that they can change their global FeministWiki password by logging into the FeministWiki, clicking on "Preferences", and then clicking on "Change password".